Hi - interesting premise. I realize that this challenge is very different from a minimum-level challenge, but I do have to agree that this certainly seems like a valid and interesting puzzle.
Specifically, I'm interpreting your challenge as "start a new Dominating character and complete the game by taking train to Northern Underrail after killing Tchort without having ever died or loading your save (other than for taking breaks) and without any cheats/character imports/etc."
This would be a specific challenge case of a more general "minimize number of deaths and resulting loads" problem statement. I realize this is all a bit obvious but I just want to state my assumptions/understanding up front.
I am not actually certain that your addition of the restriction "No Quick Tinkering" is largely relevant. It certainly might be, but I am not currently sure if the feat and point investments just to obtain that would actually make a meaningful difference in the majority of cases. In other words, are the highest risk areas actually areas that Quick Tinker helps with? If not, Quick Tinkering doesn't actually do much. For example, does Quick Tinkering protect you from DoppelGangers and Mental Subversion (Tchortlings) or Tentacles or Tithonus Ghosts? I am pretty sure those are some of the biggest threats.
I also really think you and TheAverageGortsby have already touched on a lot key points here:
Stealth is ridiculously OP, moreso I think than anything else.
If you pick your fights carefully ....
Avoiding as much combat as humanly possible is going to be key.
Having thought about this for a little bit and factoring in my current low-level experience, I think all of the following will apply at Level25 (and you have definitely mentioned some of these):
- Crafting is an absolute given because it is so absurdly (and consistently) broken, so all planning should account for at least 120 mechanics and likely ~100 electronics at least.
- Moderate Chemistry/Bio is also basically a given because it would be crazy to not have Aegis/Irongut/Jumping Bean/Focus Stims/Bull Head 100% of the time (they are insanely cheap for what they do)...and regen tailored vest probably makes sense (I haven't tested but in theory they do sounds like the single strongest combat armor type on Dominating).
- Lockpicking and hacking max (late game) are definitely partially wasted, especially since mechanics should ensure that you do not need IRIS check anyway, but definitely make sense as priority skills
- I am not actually certain whether Guns is optimal here (I have never played Psionic let alone Level 25 Psionic), but assuming you are doing Guns, obviously SmartMuzzled Hornets with FullAuto/ConcFire are easily optimal.
- I think JKK questline is by far the safest/most easily consistent via simple stealthing.
- I don't think Aimed Shot makes sense as a Feat as you should never be in a situation (I believe) where bursting or moving/consuming are not better choices. Early on things are so much easier and re-attemptable that choosing a feat just for early game seems like a massive waste.
- Wherever possible, you should skip virtually every mission that involves combat unless you can formulaically win 100% of the time
- In deep caverns bee-line for the knife quest and NEVER let Eye of Tchort get active except when you have to.
- In deep caverns, the Tithonus lab is going to be insanely scary unless there are techniques I'm not aware of
- For the T44 Manual laboratory: this place is VERY scary and random to pure stealth, even assuming you use gas mask and take southern route, but fighting can also go sideways fast since there are so many adds. I would practice stealthing this area.
- I would never do the IRIS fight (mechanics is a given)
- I would never do Mushroom Forest without CAU armor and Irongut,
- I would also NEVER do the final Free Drone Base Kill mission (waaay to risky and no payoff)
- Do as few Arena fights as possible (just get your title and recognized by an Oligarch)
- I would always stealth lunatic mall (a lot on the line / nerve wracking for sure, so practice is important, but since this can be done at lvl10 you should have an ENORMOUS margin in practice)
- Tchort fight is also going to be scary. There are so many random ways to get killed or screwed by adds/tentacles even with Mutagen puzzle+TNT on tanks, but maybe not as bad as I think if you are fully optimized and have tons of drugs
I think by far the scariest moments are all going to be in Deep Caverns (by a massive margin). Have you done any testing or practice with your ideal 25 Character there? I don't think that anything that comes before DC will be anywhere near as troublesome with planning. Tithonus Lab in particular strikes me as the single most insane random showstopper with no recourse, so I'm very curious if there are in fact ways to mitigate the risk here.